docs: def spklef(filename):
      """
      Load an ephemeris file for use by the readers.  Return that file's
      handle, to be used by other SPK routines to refer to the file.
  
      http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/spklef_c.html
  
      :param filename: Name of the file to be loaded.
      :type filename: str
      :return: Loaded file's handle.
      :rtype: int
      """
      filename = stypes.stringToCharP(filename)
      handle = ctypes.c_int()
      libspice.spklef_c(filename, ctypes.byref(handle))
      return handle.value